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  • richardmitnick 1:42 pm on January 2, 2019 Permalink | Reply
    Tags: , , , , Breathtaking touchdown, , , Science Magazine   

    From Science Magazine: “Japan’s asteroid mission faces ‘breathtaking’ touchdown” 

    From Science Magazine

    Jan. 2, 2019
    Dennis Normile

    Hayabusa2 imaged its shadow during a rehearsal descent. JAXA

    JAXA/Hayabusa 2 Credit: JAXA/Akihiro Ikeshita

    Japan’s Hayabusa mission made history in 2010 for bringing back to Earth the first samples ever collected on an asteroid. But the 7-year, 4-billion-kilometer odyssey was marked by degraded solar panels, innumerable mechanical failures, and a fuel explosion that knocked the spacecraft into a tumble and cut communications with ground control for 2 months. When planning its encore, Hayabusa2, Japan’s scientists and engineers were determined to avoid such drama. They made components more robust, enhanced communications capabilities, and thoroughly tested new technologies.

    But the target asteroid, Ryugu, had fresh surprises in store. “By looking at the details of every asteroid ever studied, we had expected to find at least some wide flat area suitable for a landing,” says Yuichi Tsuda, Hayabusa2’s project manager at the Japan Aerospace Exploration Agency’s Institute of Space and Astronautical Science (ISAS), which is headquartered in Sagamihara. Instead, when the spacecraft reached Ryugu in June 2018—at 290 million kilometers from Earth—it found a cragged, cratered, boulder-strewn surface that makes landing a daunting challenge. The first sampling touchdown, scheduled for October, was postponed until at least the end of this month, and at a symposium here on 21 and 22 December, ISAS engineers presented an audacious new plan to make a pinpoint landing between closely spaced boulders. “It’s breathtaking,” says Bruce Damer, an origins of life researcher at the University of California, Santa Cruz.

    Yet most everything else has gone according to plan since Hayabusa2 was launched in December 2014. Its cameras and detectors have already provided clues to the asteroid’s mass, density, and mineral and elemental composition, and three rovers dropped on the asteroid have examined the surface. At the symposium, ISAS researchers presented early results, including evidence of an abundance of organic material and hints that the asteroid’s parent body once held water. Those findings “add to the evidence that asteroids rather than comets brought water and organic materials to Earth,” says project scientist Seiichiro Watanabe of Nagoya University in Japan.

    Ryugu is 1 kilometer across and 900 meters top to bottom, with a notable bulge around the equator, like a diamond. Visible light observations and computer modeling suggest it’s a porous pile of rubble that likely agglomerated dust, rocks, and boulders after another asteroid or planetesimal slammed into its parent body during the early days of the solar system. Ryugu spins around its own axis once every 7.6 hours, but simulations suggest that during the early phase of its formation, it had a rotation period of only 3.5 hours. That probably produced the bulge, by causing surface landslides or pushing material outward from the core, Watanabe says. Analyzing surface material from the equator in an Earth-based laboratory could offer support for one of those scenarios, he adds. If the sample has been exposed to space weathering for a long time, it was likely moved there by landslides; if it is relatively fresh, it probably migrated from the asteroid’s interior.

    So far, Hayabusa2 has not detected water on or near Ryugu’s surface. But its infrared spectrometer has found signs of hydroxide-bearing minerals that suggest water once existed either on the parent body or on the asteroid, says Mutsumi Komatsu, a planetary materials scientist at the Graduate University for Advanced Studies in Hayama, Japan. The asteroid’s high porosity also suggests it once harbored significant amounts of water or ice and other volatile compounds that later escaped, Watanabe says. Asteroids such as Ryugu are rich in carbon as well, and they may have been responsible for bringing both water and carbon, life’s key building block, to a rocky Earth early in its history. (Comets, by contrast, are just 3% to 5% carbon.)

    Support for that theory, known as the late heavy bombardment, comes from another asteroid sample return mission now in progress. Early last month, NASA’s OSIRISREx reached asteroid Bennu, which is shaped like a spinning top as well and, the U.S. space agency has reported, has water trapped in the soil. “We’re lucky to be able to conduct comparative studies of these two asteroid brothers,” Watanabe says.

    Geologist Stephen Mojzsis of the University of Colorado in Boulder is not convinced such asteroids will prove to be the source of Earth’s water; there are other theories, he says, including the possibility that a giant Jupiter-like gaseous planet migrated from the outer to the inner solar system, bringing water and other molecules with it around the time Earth was formed. Still, findings on Ryugu’s shape and composition “scientifically, could be very important,” he says.

    Some new details come from up-close looks at the asteroid’s surface. On 21 September, Hayabusa2 dropped a pair of rovers the size of a birthday cake, named Minerva-II1A and -II1B, on Ryugu’s northern hemisphere. Taking advantage of its low gravity to hop autonomously, they take pictures that have revealed “microscopic features of the surface,” Tsuda says. And on 5 October, Hayabusa2 released a rover developed by the German and French space agencies that analyzed soil samples in situ and returned additional pictures.

    The ultimate objective, to bring asteroid samples back to Earth, will allow lab studies that can reveal much more about the asteroid’s age and content. ISAS engineers programmed the craft to perform autonomous landings, anticipating safe touchdown zones at least 100 meters in diameter. Instead, the biggest safe area within the first landing zone turned out to be just 12 meters wide.

    That will complicate what was already a nail-biting operation. Prior to each landing, Hayabusa2 planned to drop a small sphere sheathed in a highly reflective material to be used as a target, to ensure the craft is moving in sync with the asteroid’s rotation. Gravity then pulls the craft down gently until a collection horn extending from its underside makes contact with the asteroid; after a bulletlike projectile is fired into the surface, soil and rock fragments hopefully ricochet into a catcher within the horn. For safety, the craft has to steer clear of rocks larger than 70 centimeters.

    During a rehearsal in late October, Hayabusa2 released a target marker above the 12-meter safe circle; unfortunately, it came to rest more than 10 meters outside the zone. But it is just 2.9 meters away from the edge of a second possible landing site that’s 6 meters in diameter. Engineers now plan to have the craft first hover above the target marker and then move laterally to be above the center of one of the two sites. Because the navigation camera points straight down, the target marker will be outside the camera’s field of view as Hayabusa2 descends, leaving the craft to navigate on its own.

    “We are now in the process of selecting which landing site” to aim for, says Fuyuto Terui, who is in charge of mission guidance, navigation, and control. Aiming at the smaller zone means Hayabusa2 can keep the target marker in sight until the craft is close to the surface; the bigger zone gives more leeway for error, but the craft will lose its view of the marker earlier in the descent.

    Assuming the craft survives the first landing, plans call for Hayabusa2 to blast a 2-meter-deep crater into Ryugu’s surface at another site a few months later, by hitting it with a 2-kilogram, copper projectile. This is expected to expose subsurface material for observations by the craft’s cameras and sensors; the spacecraft may collect some material from the crater as well, using the same horn device. There could be a third touchdown, elsewhere on the asteroid. If all goes well, Hayabusa2 will make it back to Earth with its treasures in 2020.

    See the full article here .


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  • richardmitnick 12:14 pm on December 19, 2018 Permalink | Reply
    Tags: , Discovery of recent Antarctic ice sheet collapse raises fears of a new global flood, , Glaciologists worry about the present-day stability of the West Antarctic Ice Sheet, Science Magazine   

    From Science Magazine: “Discovery of recent Antarctic ice sheet collapse raises fears of a new global flood” 

    From Science Magazine

    Dec. 18, 2018
    Paul Voosen

    A 30-kilometer crack angles across the Pine Island Glacier, a vulnerable part of the West Antarctic Ice Sheet. NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team/Flickr

    Some 125,000 years ago, during the last brief warm period between ice ages, Earth was awash. Temperatures during this time, called the Eemian, were barely higher than in today’s greenhouse-warmed world. Yet proxy records show sea levels were 6 to 9 meters higher than they are today, drowning huge swaths of what is now dry land.

    Scientists have now identified the source of all that water: a collapse of the West Antarctic Ice Sheet. Glaciologists worry about the present-day stability of this formidable ice mass. Its base lies below sea level, at risk of being undermined by warming ocean waters, and glaciers fringing it are retreating fast. The discovery, teased out of a sediment core and reported last week at a meeting of the American Geophysical Union in Washington, D.C., validates those concerns, providing evidence that the ice sheet disappeared in the recent geological past under climate conditions similar to today’s. “We had an absence of evidence,” says Anders Carlson, a glacial geologist at Oregon State University in Corvallis, who led the work. “I think we have evidence of absence now.”

    If it holds up, the finding would confirm that “the West Antarctic Ice Sheet might not need a huge nudge to budge,” says Jeremy Shakun, a paleoclimatologist at Boston College. That, in turn, suggests “the big uptick in mass loss observed there in the past decade or two is perhaps the start of that process rather than a short-term blip.” If so, the world may need to prepare for sea level to rise farther and faster than expected: Once the ancient ice sheet collapse got going, some records suggest, ocean waters rose as fast as some 2.5 meters per century.

    As an analogy for the present, the Eemian, from 129,000 to 116,000 years ago, is “probably the best there is, but it’s not great,” says Jacqueline Austermann, a geophysicist at Columbia University’s Lamont-Doherty Earth Observatory. Global temperatures were some 2°C above preindustrial levels (compared with 1°C today). But the cause of the warming was not greenhouse gases, but slight changes in Earth’s orbit and spin axis, and Antarctica was probably cooler than today. What drove the sea level rise, recorded by fossil corals now marooned well above high tide, has been a mystery.

    Scientists once blamed the melting of Greenland’s ice sheet. But in 2011, Carlson and colleagues exonerated Greenland after identifying isotopic fingerprints of its bedrock in sediment from an ocean core drilled off its southern tip. The isotopes showed ice continued to grind away at the bedrock through the Eemian. If the Greenland Ice Sheet didn’t vanish and push up sea level, the vulnerable West Antarctic Ice Sheet was the obvious suspect. But the suspicion rested on little more than simple subtraction, Shakun says. “It’s not exactly the most compelling or satisfying argument.”

    Carlson and his team set out to apply their isotope technique to Antarctica. First, they drew on archived marine sediment cores drilled from along the edge of the western ice sheet. Studying 29 cores, they identified geochemical signatures for three different bedrock source regions: the mountainous Antarctic Peninsula; the Amundsen province, close to the Ross Sea; and the area in between, around the particularly vulnerable Pine Island Glacier.

    Armed with these fingerprints, Carlson’s team then analyzed marine sediments from a single archived core, drilled farther offshore in the Bellingshausen Sea, west of the Antarctic Peninsula. A stable current runs along the West Antarctic continental shelf, picking up ice-eroded silt along the way. The current dumps much of this silt near the core’s site, where it builds up fast and traps shelled microorganisms called foraminifera, which can be dated by comparing their oxygen isotope ratios to those in cores with known dates. Over a stretch of 10 meters, the core contained 140,000 years of built-up silt.

    For most of that period, the silt contained geochemical signatures from all three of the West Antarctic bedrock regions, the team reported, suggesting continuous ice-driven erosion. But in a section dated to the early Eemian, the fingerprints winked out: first from the Pine Island Glacier, then from the Amundsen province. That left only silt from the mountainous peninsula, where glaciers may have persisted. “We don’t see any sediments coming from the much larger West Antarctic Ice Sheet, which we’d interpret to mean that it was gone. It didn’t have that erosive power anymore,” Carlson says.

    He concedes that the dating of the core is not precise, which means the pause in erosion may not have taken place during the Eemian. It is also possible that the pause itself is illusory—that ocean currents temporarily shifted, sweeping silt to another site.

    More certainty is on the way. Next month, the International Ocean Discovery Program’s JOIDES Resolution research ship will begin a 3-month voyage to drill at least five marine cores off West Antarctica.

    JOIDES Resolution research ship

    “That’s going to be a great test,” Carlson says. Meanwhile, he hopes to get his own study published in time to be included in the next United Nations climate report. In the 2001 and 2007 reports, West Antarctic collapse was not even considered in estimates of future sea level; only in 2013 did authors start to talk about an Antarctic surprise, he says. Research is due by December 2019. “We gotta beat that deadline.”

    See the full article here .


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  • richardmitnick 2:51 pm on November 29, 2018 Permalink | Reply
    Tags: , , , Blazing quasars reveal the universe hit ‘peak star birth’ 3 million to 4 million years after the big bang, , Science Magazine   

    From Science Magazine: “Blazing quasars reveal the universe hit ‘peak star birth’ 3 million to 4 million years after the big bang” 

    From Science Magazine

    Nov. 29, 2018
    Sid Perkins

    DESY/Science Communication Lab

    When were most of the universe’s stars born? Scientists have long known that the answer is “long ago.” But a new study that scrutinizes the radiation from blazing quasars suggests a far more precise answer: some 3 million to 4 billion years after the big bang.

    Blazing quasars, or “blazars,” are galaxies whose intense brightness is fueled in large part by gas, dust, and stars being sucked into the supermassive black holes that lie at their centers. Unlike most distant stars and galaxies, blazars pump out gamma rays that can be picked up by sensors on space-based observatories orbiting Earth. As material spirals inward along the plane of the galaxy’s disk, powerful beams of radiation (above) emerge along the galaxy’s rotational axis. When one of those spotlightlike beams is pointed toward Earth, the blazars appear particularly bright.

    In the new study, researchers looked at the radiation beamed toward Earth by more than 700 blazars scattered across the sky. Analyzing the blazars’ gamma ray emissions, they found that some were blocked more effectively than others. That’s significant because when photons from the gamma rays travel through space, they can interact with the low-energy photons from stars to create subatomic particles like electrons and protons. So the more gamma ray emissions blocked, the thicker the fog of photons in that part of intergalactic space—and the more stars required to make them.

    Matching the “foggy” regions up to the distance of the blazars—between 200 million and 11.6 billion light-years from Earth—the researchers were able to determine rates of star formation for those regions, accounting for more than 90% of the history of the universe, they report today in Science. Peak rates of star birth, which were about 10 times higher than today’s rates, occurred between 9.7 billion and 10.7 billion years ago.

    See the full article here .


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  • richardmitnick 4:02 pm on November 20, 2018 Permalink | Reply
    Tags: , , Norwegian REV Big Boat Big Scence, , Science Magazine   

    From Science Magazine: “Norwegian billionaire funds deluxe deep ocean research ship” 

    From Science Magazine

    Nov. 19, 2018
    Erik Stokstad

    Twice as big as most research ships, the REV (seen in an artist’s concept) can operate in polar regions.

    “A dream vessel” is what Joana Xavier, a sponge expert at the University of Porto in Portugal, calls a new research ship due to launch in 2021. Funded by a Norwegian billionaire, the 183-meter-long Research Expedition Vessel (REV) will be the largest such ship ever built, more than twice the length of most rivals. Engineered to endure polar ice, punishing weather, and around-the-world voyages, the REV will not only be big and tough, but packed with top-of-the-line research gear—and luxurious accommodations. Its full capabilities were detailed for the first time last week at a meeting on deep-sea exploration at The Royal Society in London.

    The $350 million ship, under construction in a Black Sea shipyard in Romania, is owned by Kjell Inge Røkke, 60, who made his fortune in fishing, offshore oil, and other marine industries. In October, he promised an additional $150 million to REV Ocean in Fornebu, Norway, to operate the ship for at least 3 years, giving scientists free access. Røkke started the foundation last year to find solutions to climate change, ocean acidification, overfishing, and marine pollution. “The scale of the investment and commitment is astounding,” says Victor Zykov, science director of the Schmidt Ocean Institute, a charity in Palo Alto, California, that has its own research vessel, the Falkor.

    Many national research fleets are aging and shrinking. Since 2005, for example, the U.S. academic fleet has declined from 27 vessels to 18, and by 2025 it will it drop to 16 ships. As a result, marine scientists can face long waits for ship time. “If I want to know what’s happening in a particular place, it might not work out within a decade,” says Antje Boetius, an oceanographer and director of the Alfred Wegener Institute in Bremerhaven, Germany. Philanthropists have launched several vessels to help shorten the queue, but few are dedicated to research, and all are dwarfed by the REV.

    It offers room for 60 researchers and large areas for science and engineering. It will have trawls for capturing marine life and a remotely operated vehicle (ROV) for on-the-spot observations, a rare combination, and much else. “The idea that all the assets are on the ship, and you can pick and choose, that is tremendous,” says Ajit Subramaniam, a microbial oceanographer at the Lamont-Doherty Earth Observatory of Columbia University. The ROV, capable of 6000-meter descents, can be launched through large side doors or a moon pool in the hull. A pair of ship-borne helicopters can release smaller autonomous underwater vehicles (AUVs), which don’t need tethers to the main vessel. “Think of it as an aircraft carrier for robotics,” says Chris German, a marine geochemist at Woods Hole Oceanographic Institution in Massachusetts. The REV will also have a crewed submersible, probably one capable of descending 2000 meters.

    The main trawl, designed by Røkke’s company Aker BioMarine for harvesting krill in the Southern Ocean, can remain 3000 meters deep while funneling fish to a tube that quickly pumps them up to the ship’s wet labs. This offers the tantalizing possibility of collecting jellyfish and other soft organisms that normally don’t survive the slow trip to the surface when the trawl is winched up, opening a porthole into marine food webs. “If the gear can sample with less damage, this would really help,” says biological oceanographer Xabier Irigoien, science director of AZTI, a nonprofit institute for marine research in Pasaia, Spain.

    The REV could also make a significant contribution to understanding fisheries on the high seas, Irigoien adds. The intergovernmental organizations that regulate fishing beyond national jurisdictions don’t own ships and can rarely afford to pay for time. Free access to the REV could help scientists fill the gaps. They might be able to track tagged tuna or sharks with AUVs, for instance, while sizing up schools of fish with the ship’s high-tech sonar. By combining data from the trawl and sonar, Irigoien says, researchers could chart potential fisheries in the deep sea before they’re exploited. The same technologies would be useful for investigating far-flung marine protected areas.

    Norwegian REV Big Boat Big Scence

    Most research vessels are spartan, but on the REV scientists will have nearly full run of the ship, including its lounges, gym, dining room, and seven-story atrium. Magne Furuholmen, an artist and former keyboardist of 1980s pop group A-ha, is choosing the art collection. The REV is also eco-friendly: It’s fuel efficient with low emissions and a broad, stable hull designed to reduce noise pollution. If it encounters a garbage patch, booms can collect up to 5 tons a day of plastic to incinerate onboard for energy.

    Alex Rogers, an oceanographer at the University of Oxford in the United Kingdom, starts next month as the full-time science director for REV Ocean. He says scheduling an expedition on the REV could be quicker and more flexible than on government research vessels, which are sometimes limited by range, budget, or scientific focus. On the other hand, working with philanthropists is not like dealing with a research funding agency. “You have to explain what you’re doing,” Rogers says. “Be prepared to communicate with them.”

    Røkke’s history could raise concerns about hidden agendas. “I think there will always be some level of suspicion from the public that a person like Røkke—who made a fortune in ocean industries—that somehow there are strings attached,” Rogers admits. So he is working with the Research Council of Norway to design an independent review process that will select projects for ship time. Rogers says the only expectation is that researchers focus on solutions and share their data after they publish. “If Alex is involved, I have faith,” says Kerry Howell, a deep-sea ecologist at the University of Plymouth in the United Kingdom. “He’s not the kind of person who would work for the dark side.”

    As for Røkke, he has no plans to run the foundation and is “very meticulous about this being fully independent and objective,” says Nina Jensen, CEO of REV Ocean. “He is serious about making a difference for the oceans.” Jensen, who studied marine biology and previously led the environmental advocacy group WWF Norway , says she told Røkke she will resign if one of his companies, Aker BP, drills for oil in Norway’s Lofoten islands, which boast rich fisheries and the largest known deep-water coral reefs.

    To help cover the costs of operation, for 4 months a year the REV will open 60% of its berths on research expeditions to paying eco-tourists. For another 4 months, the entire ship will be available as a luxury yacht. Jensen hopes benefactors will charter it as a “floating think tank” to win more support for ocean protection. Any extra funds raised will go to support early-career scientists.

    It’s an unproven model, Jensen concedes, but the REV won’t sink or float on its fundraising prowess. Røkke’s pledge last month to support operations was only his first, Jensen says. “It will not be the last.”

    See the full article here .


    Please help promote STEM in your local schools.

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  • richardmitnick 7:17 pm on November 15, 2018 Permalink | Reply
    Tags: "Younger Dryas" cooling event, , , , Hiawatha Glacier, Hidden beneath Hiawatha is a 31-kilometer-wide impact crater big enough to swallow Washington D.C., Massive crater under Greenland’s ice points to climate-altering impact in the time of humans, Science Magazine   

    From Science Magazine: “Massive crater under Greenland’s ice points to climate-altering impact in the time of humans” 

    From Science Magazine

    A 1.5-kilometer asteroid, intact or in pieces, may have smashed into an ice sheet just 13,000 years ago.

    Nov. 14, 2018
    Paul Voosen

    On a bright July day 2 years ago, Kurt Kjær was in a helicopter flying over northwest Greenland—an expanse of ice, sheer white and sparkling. Soon, his target came into view: Hiawatha Glacier, a slow-moving sheet of ice more than a kilometer thick. It advances on the Arctic Ocean not in a straight wall, but in a conspicuous semicircle, as though spilling out of a basin. Kjær, a geologist at the Natural History Museum of Denmark in Copenhagen, suspected the glacier was hiding an explosive secret. The helicopter landed near the surging river that drains the glacier, sweeping out rocks from beneath it. Kjær had 18 hours to find the mineral crystals that would confirm his suspicions.

    What he brought home clinched the case for a grand discovery. Hidden beneath Hiawatha is a 31-kilometer-wide impact crater, big enough to swallow Washington, D.C., Kjær and 21 co-authors report today in a paper in Science Advances. The crater was left when an iron asteroid 1.5 kilometers across slammed into Earth, possibly within the past 100,000 years.

    Though not as cataclysmic as the dinosaur-killing Chicxulub impact, which carved out a 200-kilometer-wide crater in Mexico about 66 million years ago, the Hiawatha impactor, too, may have left an imprint on the planet’s history.

    Artist’s reconstruction of Chicxulub crater soon after impact, 66 million years ago.

    The timing is still up for debate, but some researchers on the discovery team believe the asteroid struck at a crucial moment: roughly 13,000 years ago, just as the world was thawing from the last ice age. That would mean it crashed into Earth when mammoths and other megafauna were in decline and people were spreading across North America.

    The impact would have been a spectacle for anyone within 500 kilometers. A white fireball four times larger and three times brighter than the sun would have streaked across the sky. If the object struck an ice sheet, it would have tunneled through to the bedrock, vaporizing water and stone alike in a flash. The resulting explosion packed the energy of 700 1-megaton nuclear bombs, and even an observer hundreds of kilometers away would have experienced a buffeting shock wave, a monstrous thunder-clap, and hurricane-force winds. Later, rock debris might have rained down on North America and Europe, and the released steam, a greenhouse gas, could have locally warmed Greenland, melting even more ice.

    The news of the impact discovery has reawakened an old debate among scientists who study ancient climate. A massive impact on the ice sheet would have sent meltwater pouring into the Atlantic Ocean—potentially disrupting the conveyor belt of ocean currents and causing temperatures to plunge, especially in the Northern Hemisphere. “What would it mean for species or life at the time? It’s a huge open question,” says Jennifer Marlon, a paleoclimatologist at Yale University.

    A decade ago, a small group of scientists proposed a similar scenario [Science]. They were trying to explain a cooling event, more than 1000 years long, called the Younger Dryas, which began 12,800 years ago, as the last ice age was ending. Their controversial solution was to invoke an extraterrestrial agent: the impact of one or more comets. The researchers proposed that besides changing the plumbing of the North Atlantic, the impact also ignited wildfires across two continents that led to the extinction of large mammals and the disappearance of the mammoth-hunting Clovis people of North America. The research group marshaled suggestive but inconclusive evidence, and few other scientists were convinced. But the idea caught the public’s imagination despite an obvious limitation: No one could find an impact crater.

    Proponents of a Younger Dryas impact now feel vindicated. “I’d unequivocally predict that this crater is the same age as the Younger Dryas,” says James Kennett, a marine geologist at the University of California, Santa Barbara, one of the idea’s original boosters.

    But Jay Melosh, an impact crater expert at Purdue University in West Lafayette, Indiana, doubts the strike was so recent. Statistically, impacts the size of Hiawatha occur only every few million years, he says, and so the chance of one just 13,000 years ago is small. No matter who is right, the discovery will give ammunition to Younger Dryas impact theorists—and will turn the Hiawatha impactor into another type of projectile. “This is a hot potato,” Melosh tells Science. “You’re aware you’re going to set off a firestorm?”

    It started with a hole. In 2015, Kjær and a colleague were studying a new map of the hidden contours under Greenland’s ice. Based on variations in the ice’s depth and surface flow patterns, the map offered a coarse suggestion of the bedrock topography—including the hint of a hole under Hiawatha.

    Kjær recalled a massive iron meteorite in his museum’s courtyard, near where he parks his bicycle. Called Agpalilik, Inuit for “the Man,” the 20-ton rock is a fragment of an even larger meteorite, the Cape York, found in pieces on northwest Greenland by Western explorers but long used by Inuit people as a source of iron for harpoon tips and tools. Kjær wondered whether the meteorite might be a remnant of an impactor that dug the circular feature under Hiawatha. But he still wasn’t confident that it was an impact crater. He needed to see it more clearly with radar, which can penetrate ice and reflect off bedrock.

    Kjær’s team began to work with Joseph MacGregor, a glaciologist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who dug up archival radar data. MacGregor found that NASA aircraft often flew over the site on their way to survey Arctic sea ice, and the instruments were sometimes turned on, in test mode, on the way out. “That was pretty glorious,” MacGregor says.

    The radar pictures more clearly showed what looked like the rim of a crater, but they were still too fuzzy in the middle. Many features on Earth’s surface, such as volcanic calderas, can masquerade as circles. But only impact craters contain central peaks and peak rings, which form at the center of a newborn crater when—like the splash of a stone in a pond—molten rock rebounds just after a strike. To look for those features, the researchers needed a dedicated radar mission.

    Coincidentally, the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, had just purchased a next-generation ice-penetrating radar to mount across the wings and body of their Basler aircraft, a twin-propeller retrofitted DC-3 that’s a workhorse of Arctic science. But they also needed financing and a base close to Hiawatha.

    Kjær took care of the money. Traditional funding agencies would be too slow, or prone to leaking their idea, he thought. So he petitioned Copenhagen’s Carlsberg Foundation, which uses profits from its global beer sales to finance science. MacGregor, for his part, enlisted NASA colleagues to persuade the U.S. military to let them work out of Thule Air Base, a Cold War outpost on northern Greenland, where German members of the team had been trying to get permission to work for 20 years. “I had retired, very serious German scientists sending me happy-face emojis,” MacGregor says.

    NASA and German aircraft used radar to see the contours of an impact crater beneath the ice of Hiawatha Glacier. JOHN SONNTAG/NASA

    Three flights, in May 2016, added 1600 kilometers of fresh data from dozens of transits across the ice—and evidence that Kjær, MacGregor, and their team were onto something. The radar revealed five prominent bumps in the crater’s center, indicating a central peak rising some 50 meters high. And in a sign of a recent impact, the crater bottom is exceptionally jagged. If the asteroid had struck earlier than 100,000 years ago, when the area was ice free, erosion from melting ice farther inland would have scoured the crater smooth, MacGregor says. The radar signals also showed that the deep layers of ice were jumbled up—another sign of a recent impact. The oddly disturbed patterns, MacGregor says, suggest “the ice sheet hasn’t equilibrated with the presence of this impact crater.”

    But the team wanted direct evidence to overcome the skepticism they knew would greet a claim for a massive young crater, one that seemed to defy the odds of how often large impacts happen. And that’s why Kjær found himself, on that bright July day in 2016, frenetically sampling rocks all along the crescent of terrain encircling Hiawatha’s face. His most crucial stop was in the middle of the semicircle, near the river, where he collected sediments that appeared to have come from the glacier’s interior. It was hectic, he says—”one of those days when you just check your samples, fall on the bed, and don’t rise for some time.”

    In that outwash, Kjær’s team closed its case. Sifting through the sand, Adam Garde, a geologist at the Geological Survey of Denmark and Greenland in Copenhagen, found glass grains forged at temperatures higher than a volcanic eruption can generate. More important, he discovered shocked crystals of quartz. The crystals contained a distinctive banded pattern that can be formed only in the intense pressures of extraterrestrial impacts or nuclear weapons. The quartz makes the case, Melosh says. “It looks pretty good. All the evidence is pretty compelling.”

    Now, the team needs to figure out exactly when the collision occurred and how it affected the planet.

    The Younger Dryas, named after a small white and yellow arctic flower that flourished during the cold snap, has long fascinated scientists. Until human-driven global warming set in, that period reigned as one of the sharpest recent swings in temperature on Earth. As the last ice age waned, about 12,800 years ago, temperatures in parts of the Northern Hemisphere plunged by as much as 8°C, all the way back to ice age readings. They stayed that way for more than 1000 years, turning advancing forest back into tundra.

    The trigger could have been a disruption in the conveyor belt of ocean currents, including the Gulf Stream that carries heat northward from the tropics. In a 1989 paper in Nature, Kennett, along with Wallace Broecker, a climate scientist at Columbia University’s Lamont-Doherty Earth Observatory, and others, laid out how meltwater from retreating ice sheets could have shut down the conveyor. As warm water from the tropics travels north at the surface, it cools while evaporation makes it saltier. Both factors boost the water’s density until it sinks into the abyss, helping to drive the conveyor. Adding a pulse of less-dense freshwater could hit the brakes. Paleoclimate researchers have largely endorsed the idea, although evidence for such a flood has been lacking until recently.

    Then, in 2007, Kennett suggested a new trigger. He teamed up with scientists led by Richard Firestone, a physicist at Lawrence Berkeley National Laboratory in California, who proposed a comet strike at the key moment [PNAS]. Exploding over the ice sheet covering North America, the comet or comets would have tossed light-blocking dust into the sky, cooling the region. Farther south, fiery projectiles would have set forests alight, producing soot that deepened the gloom and the cooling. The impact also could have destabilized ice and unleashed meltwater that would have disrupted the Atlantic circulation.

    The climate chaos, the team suggested, could explain why the Clovis settlements emptied and the megafauna vanished soon afterward. But the evidence was scanty. Firestone and his colleagues flagged thin sediment layers at dozens of archaeological sites in North America. Those sediments seemed to contain geochemical traces of an extraterrestrial impact, such as a peak in iridium, the exotic element that helped cement the case for a Chicxulub impact. The layers also yielded tiny beads of glass and iron—possible meteoritic debris—and heavy loads of soot and charcoal, indicating fires.

    The team met immediate criticism. The decline of mammoths, giant sloths, and other species had started well before the Younger Dryas. In addition, no sign existed of a human die-off in North America, archaeologists said. The nomadic Clovis people wouldn’t have stayed long in any site. The distinctive spear points that marked their presence probably vanished not because the people died out, but rather because those weapons were no longer useful once the mammoths waned, says Vance Holliday, an archaeologist at The University of Arizona in Tucson. The impact hypothesis was trying to solve problems that didn’t need solving.

    The geochemical evidence also began to erode. Outside scientists could not detect the iridium spike in the group’s samples. The beads were real, but they were abundant across many geological times, and soot and charcoal did not seem to spike at the time of the Younger Dryas. “They listed all these things that aren’t quite sufficient,” says Stein Jacobsen, a geochemist at Harvard University who studies craters.

    Yet the impact hypothesis never quite died. Its proponents continued to study the putative debris layer at other sites in Europe and the Middle East. They also reported finding microscopic diamonds at different sites that, they say, could have been formed only by an impact. (Outside researchers question the claims of diamonds.)

    Now, with the discovery of Hiawatha crater, “I think we have the smoking gun,” says Wendy Wolbach, a geochemist at De-Paul University in Chicago, Illinois, who has done work on fires during the era.

    The impact would have melted 1500 gigatons of ice, the team estimates—about as much ice as Antarctica has lost because of global warming in the past decade. The local greenhouse effect from the released steam and the residual heat in the crater rock would have added more melt. Much of that freshwater could have ended up in the nearby Labrador Sea, a primary site pumping the Atlantic Ocean’s overturning circulation. “That potentially could perturb the circulation,” says Sophia Hines, a marine paleoclimatologist at Lamont-Doherty.

    Leery of the earlier controversy, Kjær won’t endorse that scenario. “I’m not putting myself in front of that bandwagon,” he says. But in drafts of the paper, he admits, the team explicitly called out a possible connection between the Hiawatha impact and the Younger Dryas.

    Banded patterns in the mineral quartz are diagnostic of shock waves from an extraterrestrial impact. ADAM GARDE, GEUS

    The evidence starts with the ice. In the radar images, grit from distant volcanic eruptions makes some of the boundaries between seasonal layers stand out as bright reflections. Those bright layers can be matched to the same layers of grit in cataloged, dated ice cores from other parts of Greenland [Science]. Using that technique, Kjær’s team found that most ice in Hiawatha is perfectly layered through the past 11,700 years. But in the older, disturbed ice below, the bright reflections disappear. Tracing the deep layers, the team matched the jumble with debris-rich surface ice on Hiawatha’s edge that was previously dated to 12,800 years ago. “It was pretty self-consistent that the ice flow was heavily disturbed at or prior to the Younger Dryas,” MacGregor says.

    Other lines of evidence also suggest Hiawatha could be the Younger Dryas impact [PNAS]. In 2013, Jacobsen examined an ice core from the center of Greenland, 1000 kilometers away. He was expecting to put the Younger Dryas impact theory to rest by showing that, 12,800 years ago, levels of metals that asteroid impacts tend to spread did not spike. Instead, he found a peak in platinum, similar to ones measured in samples from the crater site. “That suggests a connection to the Younger Dryas right there,” Jacobsen says.

    For Broecker, the coincidences add up. He had first been intrigued by the Firestone paper, but quickly joined the ranks of naysayers. Advocates of the Younger Dryas impact pinned too much on it, he says: the fires, the extinction of the megafauna, the abandonment of the Clovis sites. “They put a bad shine on it.” But the platinum peak Jacobsen found, followed by the discovery of Hiawatha, has made him believe again. “It’s got to be the same thing,” he says.

    Yet no one can be sure of the timing. The disturbed layers could reflect nothing more than normal stresses deep in the ice sheet. “We know all too well that older ice can be lost by shearing or melting at the base,” says Jeff Severinghaus, a paleoclimatologist at the Scripps Institution of Oceanography in San Diego, California. Richard Alley, a glaciologist at Pennsylvania State University in University Park, believes the impact is much older than 100,000 years and that a subglacial lake can explain the odd textures near the base of the ice. “The ice flow over growing and shrinking lakes interacting with rough topography might have produced fairly complex structures,” Alley says.

    A recent impact should also have left its mark in the half-dozen deep ice cores drilled at other sites on Greenland, which document the 100,000 years of the current ice sheet’s history. Yet none exhibits the thin layer of rubble that a Hiawatha-size strike should have kicked up. “You really ought to see something,” Severinghaus says.

    Brandon Johnson, a planetary scientist at Brown University, isn’t so sure. After seeing a draft of the study, Johnson, who models impacts on icy moons such as Europa and Enceladus, used his code to recreate an asteroid impact on a thick ice sheet. An impact digs a crater with a central peak like the one seen at Hiawatha, he found, but the ice suppresses the spread of rocky debris. “Initial results are that it goes a lot less far,” Johnson says.

    In 2016, Kurt Kjær looked for evidence of an impact in sand washed out from underneath Hiawatha Glacier. He would find glassy beads and shocked crystals of quartz.

    Even if the asteroid struck at the right moment, it might not have unleashed all the disasters envisioned by proponents of the Younger Dryas impact. “It’s too small and too far away to kill off the Pleistocene mammals in the continental United States,” Melosh says. And how a strike could spark flames in such a cold, barren region is hard to see. “I can’t imagine how something like this impact in this location could have caused massive fires in North America,” Marlon says.

    It might not even have triggered the Younger Dryas. Ocean sediment cores show no trace of a surge of freshwater into the Labrador Sea from Greenland, says Lloyd Keigwin, a paleoclimatologist at the Woods Hole Oceanographic Institution in Massachusetts. The best recent evidence, he adds, suggests a flood into the Arctic Ocean through western Canada instead [Nature Geoscience].

    An external trigger may be unnecessary in any case, Alley says. During the last ice age, the North Atlantic saw 25 other cooling spells, probably triggered by disruptions to the Atlantic’s overturning circulation. None of those spells, known as Dansgaard-Oeschger (D-O) events, was as severe as the Younger Dryas, but their frequency suggests an internal cycle played a role in the Younger Dryas, too. Even Broecker agrees that the impact was not the ultimate cause of the cooling. If D-O events represent abrupt transitions between two regular states of the ocean, he says, “you could say the ocean was approaching instability and somehow this event knocked it over.”

    Still, Hiawatha’s full story will come down to its age. Even an exposed impact crater can be a challenge for dating, which requires capturing the moment when the impact altered existing rocks—not the original age of the impactor or its target. Kjær’s team has been trying. They fired lasers at the glassy spherules to release argon for dating, but the samples were too contaminated. The researchers are inspecting a blue crystal of the mineral apatite for lines left by the decay of uranium, but it’s a long shot. The team also found traces of carbon in other samples, which might someday yield a date, Kjær says. But the ultimate answer may require drilling through the ice to the crater floor, to rock that melted in the impact, resetting its radioactive clock. With large enough samples, researchers should be able to pin down Hiawatha’s age.

    Given the remote location, a drilling expedition to the hole at the top of the world would be costly. But an understanding of recent climate history—and what a giant impact can do to the planet—is at stake. “Somebody’s got to go drill in there,” Keigwin says. “That’s all there is to it.”

    See the full article here .


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  • richardmitnick 5:08 pm on November 13, 2018 Permalink | Reply
    Tags: Antlia 2 - large strangely dim galaxy found lurking on far side of Milky Way, , , , , GAIA works its magic again in this find, Science Magazine   

    From Science Magazine: “Large, strangely dim galaxy found lurking on far side of Milky Way” 

    From Science Magazine

    Nov. 13, 2018
    Adam Mann

    Antlia 2 (upper left), hidden on the Milky Way’s far side, is as big as the Large Magellanic Cloud (lower right) but much dimmer. (A bright, artificial blob representing Antlia 2 was added to show its location.) G. Torrealba, Academia Sinica, Taiwan; V. Belokurov, Cambridge, U.K. and CCA, New York, U.S., based on an image by ESO/S. Brunie

    Circling our galaxy is a stealthy giant. Astronomers have discovered a dwarf galaxy, called Antlia 2, that is one-third the size of the Milky Way itself. As big as the Large Magellanic Cloud, the galaxy’s largest companion, Antlia 2 eluded detection until now because it is 10,000 times fainter. Such a strange beast challenges models of galaxy formation and dark matter, the unseen stuff that helps pull galaxies together.

    “It’s a very odd object and kind of exciting because we don’t know yet how to interpret all of its properties,” says Andrey Kravtsov of The University of Chicago in Illinois, who was not involved in the work.

    The galaxy was discovered with data from the European Space Agency’s Gaia satellite, a space telescope measuring the motions and properties of more than 1 billion stars in and around the Milky Way.

    ESA/GAIA satellite

    Gabriel Torrealba, an astronomy postdoc at the Academia Sinica in Taipei, decided to sift the data for RR Lyrae stars. These old stars, often found in dwarf galaxies, shine with a throbbing blue light that pulses at a rate signaling their inherent brightness, allowing researchers to pin down their distance.

    “RR Lyrae are so rare at these distances that even if you see two, you question why they are together,” says Vasily Belokurov, an astronomer at the University of Cambridge in the United Kingdom and a collaborator on the discovery. When the team found three, some 420,000 light-years away, it was “an overwhelming signal” of a large cluster of stars in that location, Belokurov says. But because the RR Lyrae stars lie on the far side of the disk of the Milky Way and its obstructing veil of stars and gas, finding their companions was not easy.

    Gaia data helped the team see past the foreground stars. Objects in the Milky Way’s disk are close enough for Gaia to measure their parallax: a shift in their apparent position as Earth moves around the sun. More distant stars appear fixed in one spot. After removing the parallax-bearing stars, the researchers homed in on more than 100 red giant stars moving together in the constellation Antlia, they report in a paper posted to the preprint server arXiv this week. The giants mark out a sprawling companion galaxy 100 times less massive than anything of similar size, with far fewer stars.

    To explain such a diffuse galaxy, Belokurov suggests that early in Antlia 2’s history, many young stars exploded as violent supernovae. This would have blown gas and dust out of the galaxy, weakening its gravity so that it puffed up. An abundance of the heavy elements that are strewn from the guts of exploding stars adds credibility to this idea, says Shea Garrison-Kimmel, an astrophysicist at the California Institute of Technology in Pasadena. Antlia 2 could also have lost matter as stars were tugged away by gravitational tidal forces as it orbited around the larger Milky Way.

    Even so, its disproportionate size is hard to explain. Galaxies are thought to have formed when the gravity of enormous clumps of dark matter drew in enough ordinary matter to fuel the birth of stars. The team speculates that Antlia 2 might have been born from a fluffier, faster-moving type of dark matter than current models hypothesize.

    To Garrison-Kimmel, one example isn’t enough to say the dark matter in Antlia 2 is different from that in the Milky Way and its other satellites. “There’s nothing in this one galaxy that screams to me that we need to rethink dark matter,” he says. “But if there are a lot of these, then we might need to take a step back and ask what’s going on.”

    That could happen now that astronomers know how to find these big, elusive companions. “I think this object is a harbinger,” Kravtsov says. “A taste of things to come.”

    See the full article here .


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  • richardmitnick 12:40 pm on November 7, 2018 Permalink | Reply
    Tags: , Metric system overhaul will dethrone the one true kilogram, Science Magazine, SI-International System of Units   

    From Science Magazine: “Metric system overhaul will dethrone the one, true kilogram” 

    From Science Magazine

    Nov. 6, 2018
    Adrian Cho

    The atoms in a sphere of silicon-28 were counted to fix the Avogadro constant and redefine the mole. A copy of Le Grand K, the kilogram standard, can be seen in the sphere’s reflection. PTB

    Like an aging monarch, Le Grand K is about to bow to modernity. For 130 years, this gleaming cylinder of platinum-iridium alloy has served as the world’s standard for mass. Kept in a bell jar and locked away at the International Bureau of Weights and Measures (BIPM) in Sèvres, France, the weight has been taken out every 40 years or so to calibrate similar weights around the world. Now, in a revolution far less bloody than the one that cost King Louis XVI his head, it will cede its throne as the one, true kilogram.

    When the 26th General Conference on Weights and Measures (CGPM) convenes next week in Versailles, France, representatives of the 60 member nations are expected to vote to redefine the International System of Units (SI) so that four of its base units—the kilogram, ampere, kelvin, and mole—are defined indirectly, in terms of physical constants that will be fixed by fiat. They’ll join the other three base units—the second, meter, and candela (a measure of a light’s perceived brightness)—that are already defined that way. The rewrite eliminates the last physical artifact used to define a unit, Le Grand K.

    The shift aims to make the units more stable and allow investigators to develop ever more precise and flexible techniques for converting the constants into measurement units. “That’s the beauty of the redefinition,” says Estefanía de Mirandés, a physicist at BIPM. “You are not limited to one technology.” But even proponents of the arcane changes acknowledge they may bewilder nonexperts. “Cooler heads have said, ‘What are we going to do about teaching people to use this?’” says Jon Pratt, a physicist at the U.S. National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland.

    The new SI generalizes the trade-off already exploited to define the meter more precisely in terms of the speed of light. Until 1983, light’s speed was something to be measured in terms of independently defined meters and seconds. However, that year, the 17th CGPM defined the speed of light as exactly 299,792,458 meters per second. The meter then became the measurable thing: the distance light travels in 1/299,792,458 seconds. (The second was pegged to the oscillations of microwave radiation from cesium atoms in 1967.)

    The new SI plays the same game with the other units. For example, it defines the kilogram in terms of the Planck constant, which pops up all over quantum mechanics. The constant is now fixed as exactly 6.62607015×10-34 kilogram meters squared per second. Because the kilogram appears in that definition, any experiment that previously measured the constant becomes a way to measure out a kilogram instead.

    Such experiments are much harder than clocking light speed, a staple of undergraduate physics. One technique employs a device called a Kibble balance, which is a bit like the mythical scales of justice. A mass on one side is counterbalanced by the electric force produced by an electrical coil on the other side, hanging in a magnetic field. To balance the weight, a current must run through the coil. Researchers can equate the mass to that current times an independent voltage generated when they remove the mass and move the coil up and down in the magnetic field.


    Metric makeover 2018


    The real trickiness enters in sizing up the current and voltage, with quantum mechanical devices that do it in terms of the charge of the electron and the Planck constant. Now that the new SI has fixed those constants, the balance can be used to mete out a slug with a mass of exactly 1 kilogram. The redefinition also effectively makes the quantum techniques the SI standards for measuring voltages and currents, says James Olthoff, a NIST physicist. Until now, the SI has defined the ampere impractically, in terms of the force between infinitely long current carrying wires separated by a meter.

    But applying the complex new definitions will baffle anybody without an advanced degree in physics, argues Gary Price, a metrologist in Sydney, Australia, who used to advise Australia’s National Standards Commission. In fact, he argues, the new SI fails to meet one of the basic requirements of a units system, which is to specify the amount of mass with which to measure masses, the amount of length with which to measure lengths, and so on. “The new SI is not weights and measures at all,” Price says.

    Metrologists considered more intuitive redefinitions, Olthoff says. For example, you could define the kilogram as the mass of some big number of a particular atom. But such a standard would be impractical, Olthoff says. Somewhat ironically, researchers have already counted the atoms in exquisitely round, 1-kilogram spheres of silicon-28 to fix an exact value for the mole, formerly defined as the measurable number of carbon-12 atoms in 12 grams of the stuff.

    If approved, the new SI goes into effect in May 2019. In the short term, little will change, Pratt says. NIST will continue to propagate weight standards by calibrating its kilogram weights—although now it will do so with its Kibble balance. Eventually, Pratt says, researchers could develop tabletop balances that companies could use to calibrate their own microgram weights.

    Next up is a rethink of the second. Metrologists are developing more precise atomic clocks that use optical radiation with higher frequencies than the current cesium standard. They should form the basis for a finer definition of the second, De Mirandés says, perhaps in 2030.

    As for Le Grand K, BIPM will keep it and will periodically calibrate it as a secondary mass standard, De Mirandés says. That’s a fairly dignified end for a deposed French king.

    See the full article here .


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  • richardmitnick 11:12 pm on October 30, 2018 Permalink | Reply
    Tags: Europe’s billion-euro quantum flagship hands out first grants, Science Magazine   

    From Science Magazine: “Europe’s billion-euro quantum flagship hands out first grants” 

    From Science Magazine

    Oct. 29, 2018
    Edwin Cartlidge

    Quantum computers made of superconducting circuits could be the first to outpace conventional computers. IBM Research/Flickr (CC BY-ND 2.0)

    The first phase of Europe’s decadelong, billion-euro program to turn its quantum technology research into commercial products has come into focus. At an event held in Vienna on 29 October, the European Union announced the first €132 million of its quantum flagship initiative will be split between 20 continent-wide consortia over the next 3 years to develop new kinds of quantum sensors, communications, and computers.

    Backers hope the investment will keep Europe from being overtaken in a potent new area of technology. “It’s important to start an applications sector to allow industry to grow in Europe,” says Ian Walmsley, of the University of Oxford in the United Kingdom, and a member of the steering group that formulated the flagship. “No doubt it’s growing elsewhere in the world.” But it remains uncertain how the rest of the flagship will be paid for, and whether it will inject life into a fledgling European quantum industry.

    Physicists have begun to find commercial applications for the strange laws of quantum mechanics, which allow a subatomic particle to be in two states at the same time and a measurement on one particle to instantly affect another, distant particle. For example, Swiss company ID Quantique, set up in 2001, sells equipment exploiting the quantum properties of photons to create uncrackable encryptions for banks and governments.

    Basic research in quantum mechanics has flourished in Europe. But China is spending billions of dollars to commercialize quantum technology, including a satellite to send quantum-encrypted messages through space, launched in 2016—a first step toward a quantum internet. Meanwhile, the U.S. Congress is considering a $1.3 billion quantum initiative, and U.S. companies including Google, IBM, Intel, and Microsoft have already spent hundreds of millions of dollars to try to build a quantum computer that could outstrip conventional machines on certain tasks.

    Such investment has been scarce in Europe, where companies without the huge cash reserves of U.S. tech firms have been reluctant to take risks. The quantum flagship—the third EU flagship research program after ones on graphene and the human brain—is intended to compensate. Without such support, says flagship spokesperson Tommaso Calarco of the Jülich research center in Germany, “the ideas that were developed and are still being developed in Europe could be converted into companies and jobs elsewhere.”

    The program was announced in 2016, and grant proposals from 140 consortia—each a mixture of academics and industrialists—were received earlier this year, before being whittled down to the 20 winners across five categories. Seven of the winners will pursue basic science while many of the remaining consortia will develop commercial prototypes. Four winners are in the category of quantum communication and include a Dutch-led proposal to develop a blueprint for a quantum internet. Two more will plunge into the race for quantum supremacy, which means executing a specific algorithm that the best classical computers can’t handle.

    These groups might find themselves trailing Google, which aims to reach that milestone either later this year or early next using quantum bits, or qubits, made in superconducting circuits, says John Martinis, the company’s head of quantum hardware in Santa Barbara, California. Thomas Monz of the University of Innsbruck in Austria, who coordinates one of the European consortia, says his group’s bid for quantum supremacy, which uses trapped ions as qubits, is based on an algorithm that will be more “meaningful”—in other words, potentially useful—than Google’s.

    A full-scale quantum computer is decades off, however. Among the consortia developing more tangible quantum devices, Florian Schreck of the University of Amsterdam and colleagues are aiming to make a portable and easy-to-use optical clock that could help telecom companies end their dependence on potentially unreliable GPS signals. Meanwhile, Christoph Nebel of the Fraunhofer Institute for Applied Solid State Physics in Freiburg, Germany, and co-workers are working on a prototype room-temperature device to supply the spin-polarized molecules needed for magnetic resonance imaging machines.

    These grants amount to just a fraction of the initiative’s €1 billion commitment. Calarco says the format of the next funding round could combine calls for fresh proposals with continued support for existing projects. But where the money will come from is in question. Funding is supposed to be split 50-50 between the European Commission and member states. But unlike other flagships, the member state funding does not end up in a central pot. Instead, these funds are earmarked for national programs that merely share the aims of the quantum flagship. Given the complexity of this arrangement, Calarco is hoping the budget for the next EU research framework, to be decided next year, will contain all of the remaining €850 million needed for the quantum flagship. “I am working hard towards that goal,” he says.

    An additional uncertainty is how Brexit—the United Kingdom’s departure from the European Union in 2019—will affect the flagship. Brexit could remove a key funding source, although the United Kingdom could strike a deal like Switzerland, which pays to participate in EU research frameworks. But Brexit’s effects on grantees will be delayed: The U.K. groups within the 20 winning consortia will participate for the full 3-year initial period. “We don’t know what form Brexit will take,” Calarco says. “So we have 3 years to sort this out.”

    See the full article here .


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  • richardmitnick 2:53 pm on October 25, 2018 Permalink | Reply
    Tags: Science Magazine, , Three Chinese teams join race to build the world’s fastest supercomputer   

    From Science: “Three Chinese teams join race to build the world’s fastest supercomputer” 

    From Science

    Tianhe-1A was the world’s fastest computer in 2010. Its successor is being developed in the same building.

    Oct. 24, 2018
    Dennis Normile

    TIANJIN, CHINA—In a cavernous room just off the marble floored lobby of China’s National Supercomputer Center of Tianjin stand more than 100 wardrobe-size black and gray metal cabinets, arranged in ranks like a marching army. They contain the Tianhe-1A supercomputer, which 8 years ago became the first Chinese machine to reign, briefly, as the world’s fastest computer, running at 2.57 petaflops (or quadrillion floating point operations per second). But just upstairs from Tianhe-1A—and off-limits to visitors—is a small prototype machine that, if successfully scaled up, could push China to the top of the rankings again. The goal is a supercomputer capable of 1 exaflop—1000 petaflops, five times faster than the current champion, the Summit supercomputer at Oak Ridge National Laboratory in Tennessee.

    ORNL IBM AC922 SUMMIT supercomputer. Credit: Carlos Jones, Oak Ridge National Laboratory/U.S. Dept. of Energy

    China is vying with the United States, Europe, and Japan to plant its flag in this rarefied realm, which will boost climate and weather modeling, human genetics studies, drug development, artificial intelligence, and other scientific uses. But its strategy is unique. Three teams are competing to build China’s machine; the Tianjin prototype has rivals at the National Supercomputing Center in Jinan and at Dawning Information Industry Co., a supercomputer manufacturer in Beijing. The Ministry of Science and Technology (MOST) will probably select two for expansion to exascale by the end of the year. The approach is a chance to spur innovation, says Bob Sorensen, a high-performance computing analyst at Hyperion Research in St. Paul. It “encourages vendors to experiment with a wide range of designs to distinguish themselves from their competitors,” he says.

    China may not be first to reach this computing milestone. Japan’s Post-K exascale computer could be running in 2020.

    Post-K exascale computer Japan

    The United States is aiming to deploy its first exascale system at Argonne National Laboratory in Lemont, Illinois, in 2021.

    Depiction of ANL ALCF Cray Shasta Aurora exascale supercomputer

    The European Union is ramping up its own program. China is aiming for 2020, but the date may slip.

    See the full article here .


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  • richardmitnick 12:51 pm on October 19, 2018 Permalink | Reply
    Tags: , , , , , Science Magazine   

    From Science Magazine: “Chemists find a recipe that may have jump-started life on Earth’ 

    From Science Magazine

    New research spells out the simple chemical steps that may have launched the RNA World. Mark Garlick/Science Source

    Oct. 18, 2018
    Robert F. Service

    In the molecular dance that gave birth to life on Earth, RNA appears to be a central player. But the origins of the molecule, which can store genetic information as DNA does and speed chemical reactions as proteins do, remain a mystery. Now, a team of researchers has shown for the first time that a set of simple starting materials, which were likely present on early Earth, can produce all four of RNA’s chemical building blocks.

    Those building blocks—cytosine, uracil, adenine, and guanine—have previously been re-created in the lab from other starting materials. In 2009, chemists led by John Sutherland at the University of Cambridge in the United Kingdom devised a set of five compounds likely present on early Earth that could give rise to cytosine and uracil, collectively known as pyrimidines. Then, 2 years ago, researchers led by Thomas Carell, a chemist at Ludwig Maximilian University in Munich, Germany, reported that his team had an equally easy way to form adenine and guanine [Nature], the building blocks known as purines. But the two sets of chemical reactions were different. No one knew how the conditions for making both pairs of building blocks could have occurred in the same place at the same time.

    Now, Carell says he may have the answer. On Tuesday, at the Origins of Life Workshop here, he reported that he and his colleagues have come up with a simple set of reactions that could have given rise to all four RNA bases.

    Carell’s story starts with only six molecular building blocks—oxygen, nitrogen, methane, ammonia, water, and hydrogen cyanide, all of which would have been present on early Earth. Other research groups had shown that these molecules could react to form somewhat more complex compounds than the ones Carell used.

    To make the pyrimidines, Carell started with compounds called cyanoacetylene and hydroxylamine, which react to form compounds called amino-isoxazoles. These, in turn, react with another simple molecule, urea, to form compounds that then react with a sugar called ribose to make one last set of intermediate compounds.

    Finally, in the presence of sulfur-containing compounds called thiols and trace amounts of iron or nickel salts, these intermediates transform into the pyrimidines cytosine and uracil. As a bonus, this last reaction is triggered when the metals in the salts harbor extra positive charges, which is precisely what occurs in the final step in a similar molecular cascade that produces the purines, adenine and guanine. Even better, the step that leads to all four nucleotides works in one pot, Carell says, offering for the first time a plausible explanation of how all of RNA’s building blocks could have arisen side by side.

    “It looks pretty good to me,” says Steven Benner, a chemist with the Foundation for Applied Molecular Evolution in Alachua, Florida. The process provides a simple way to produce all four bases under conditions consistent with those believed present on early Earth, he says.

    The process doesn’t solve all of RNA’s mysteries. For example, another chemical step still needs to “activate” each of RNA’s four building blocks to link them into the long chains that form genetic material and carry out chemical reactions. But making RNA under conditions like those present on early Earth now appears within reach.

    See the full article here .


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    • stewarthoughblog 11:31 pm on October 19, 2018 Permalink | Reply

      Some interesting science here, but mostly wildly speculative naturalism. The “molecular dance” is a myth, like Darwin’s “warm little ponds,” Oparin-Haldane primordial soup or Miller-Urey test tube goo. There are no naturalistic processes capable of any appreciable assembly of abiotic chemicals at any level that approach the basic, elemental level of assembly required for the origin of life.

      RNA, in particular, is an intermediate molecule that is easily mutated, easily contaminated, highly reactive, composed of homochiral AGCU that does not develop naturalistically and does not function at any level that produces metabolic processes or reproduce.

      The intelligently designed, highly orchestrated lab experiments are biogeochemically irrelevant to primordial Earth conditions and do no demonstrate any significant achievement relative to the origin of life.


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